Blueberry growing intense in Colorado

by guest writer Joel Reich*

Many Colorado gardeners have long lamented their inability to grow blueberries (Vaccinium corymbosum and related species). The problem stems from the fact that most of Colorado’s soils are slightly to highly alkaline, above pH 7.0 (neutral). Blueberries must have acid soils (a pH of about 5.5) in order to thrive. Unfortunately, there is just no practical way to manage Colorado soils in order to produce a pH that low.

The good news for blueberry lovers is that, with extra effort, there is a proven way to grow delicious blueberries in your Colorado garden. The keys to success are 1) plant the blueberry bushes in a medium that is primarily (or entirely) composed of sphagnum peat moss. This readily available material has a pH of approximately 5.5, so it is perfect for blueberries. Two further keys to success are: 2) make sure that the root zone always stays moist (even during warm, dry spells in winter), and 3) protect the bushes from drying winds during the winter. This can be done by wrapping the bushes with burlap or old sheets while they are dormant.

Any planting method that incorporates these three key elements should lead to success, so feel free to be creative. For those who want an established recipe for success, follow the instructions below. Keep in mind that you will need to have at least two blueberry plants of different varieties (for cross-pollination purposes) in order for the plants to set good crops.

For each plant:

- Dig a hole that is 20” deep, 30”long and 20” wide.
- Get a plastic-wrapped bale of sphagnum peat moss (3 cubic feet).
- Punch about a dozen holes in the bottom of the plastic wrap.
- Drop the bale, holes down, into your pre-dug hole. You can grow more plants in a row by dropping multiple bales in a trench. Different plants are necessary for cross-pollination as noted above.
- Cut an 8”x 8” “X” in the plastic on top of the bale and fold back flaps.
- Plant a bare-root blueberry plant directly into the peat moss (Do this in early-mid April).
- Re-close the “X” using tape, leaving about a 3” hole in the middle to accommodate the trunk of the bush.
- (optional) Install drip irrigation line by cutting a small hole at either end of the bale and feeding the line through the holes, resulting in an irrigation line that runs on top of the peat but under the plastic.
- Fertilize in early May and early July with a balanced fertilizer for acid-loving plants (i.e. Miracle Grow for Acid Loving Plants).
- Water and provide winter protection as discussed in keys to success above.
- Provide protection from “critters” as animals love blueberries too.
- Enjoy blueberries year after year!


* Joel Reich is CSU Extension horticulturist at the Boulder County Extension office in Longmont, CO where he trials blueberries and other small fruits.

Photo credit: Dladek

Grow your own chicons (Belgian endive)

Growing delicious salad greens in December in Colorado may seem a stretch to some but it’s not as far-fetched as it may seem. Belgian endive or witloof chicory will produce the tight shoots of leaves known as chicons through winter forcing. They are highly desired for gourmet salads and are used either alone or with other greens. They can also be lightly steamed and are high in vitamin C.

As discussed last post, this plant is another form of chicory, Cichorium intybus. Belgian endive requires a two stage production process. These plants are grown as a root crop during the summer (first stage), dug and stored cold for winter forcing (second stage). They require a little over 3 months for root production so plant in early July. Be sure to plant Belgian endive and not the endive/escarole/frisee seed discussed last post.

Roots can be dug after the first frost in fall depending on variety and maturity. Mature roots are 1 ¼ to 2 ¼ inches in diameter. The final harvest should be made by early December from beds mulched to avoid soil freezing. Trim tops back to 1 inch and store roots by planting in pots of dry soil or lined out in rows in open-top trays that are at least 6 inches deep and have drainage. Roots that are too long for the container can be trimmed from the bottom. Do not water after planting but make sure that soil touches all sides of the roots and air pockets are eliminated. Store in an uncovered coldframe or under an outdoor deck on a north or east side where temperatures will hold at 40 to 60 degrees F (cooler is better). Root cellars or unheated garages and garden sheds are other storage possibilities. Roots are often covered with perlite, sawdust or dry sand after soil temperatures have cooled. This keeps them cool but mulches them from extreme cold.

The mulch becomes necessary to the second stage growing process, forcing. Roots should be forced in the dark so the shoots remain yellow-white and develop a mild flavor. Light cause the shoots to turn green and taste bitter. Some home growers use a length of 4 inch diameter plastic pipe over a root planted in a pot, filling the 6 inch tall pipe with perlite or a peat-sand mixture. Containers can be watered by applying water to the soil surface at the base of the pipe and not through the top of the pipe. Keep roots moist for the 3 to 4 week forcing period. Good soil drainage is important so roots don’t rot. Harvest when shoots poke out the top of the pipe. With this pipe method, you can tip the perlite or peat-sand mixture out of the top of the pipe, lift the pipe off the shoot, and cut the chicon at the soil line.

Winter forcing can be done over time producing a stream of fresh greens. Limitations to production will be when storage becomes too warm and roots start to grow. Note that traditional varieties such as ‘Totem’ and ‘Witloof di Bruxelles’ are forced by the soil or mulch covering method in darkness. New hybrid varieties from Europe such as ‘Normato’, ‘Mitado’ and ‘Tardivo’ produce tight heads in darkness without the need for soil or mulch covering.

Photo credit: Witloof roots, Rasbak. Chicon, David.Monniaux.

Frisee – Gourmet chicory greens

Chicory (Cichorium intybus) is an interesting garden vegetable that has many forms and is known by many names including frisee, curly leaf endive, flat leafed endive or escarole, radicchio, Belgium endive, witlof and chicon. Qriginally from Europe, chicory is a weed in America with scattered plants growing in Colorado at 4000 to 7000 feet elevation. Many people think it is a native “wildflower” (see photo). It is often confused with blue flax which has one layer of petals instead of the double “wheel” of chicory flowers.

Of the selected forms for eating, the leafy vegetables include frisee sometimes sold by seed companies as Cichorium endivia. The frilly leaves (see photo) are used as a bitter fresh green in salad mixes. Flat-leafed endive (escarole) is more often used as a wilted or cooked green. Note that some people use the term frisee for frilly lettuce but lettuce is in a whole separate genus, Lactuca. The chicory group of plants is confusing enough without mixing the idea of lettuces in with them.

It’s entirely appropriate to be talking about frisee in late November as the greens are very cold hardy and can survive until early December particularly if mulched. Frisee is easy to grow in 45 days and can be planted in mid-summer for a fall crop, or in early spring as a cool season crop for harvesting before hot weather arrives. Some people blanch their crop by tying leaves in a bundle 3 days before harvest to deprive the inner leaves of light and change them to a light yellow color.

Next post will be about another fun thing to do with chicory plants - harvest roots and force the gourmet witlof (chicon) buds to grow in winter.

Photo credits: Cichorium intybus flower-Alvesgaspar, Frisee – Frank C. Muller

Leftover vegetable seed storage

Many home gardeners end up with a few seeds in a seed packet or even unopened packets of seeds. Are they worth storing for planting next year?

A dry climate is ideal for storing many vegetable seeds. Life is extended under dry conditions even if seeds are stored at warmer temperatures of 70 degrees F and not 32 degrees F. Exceptions are bean and okra seeds that develop hard coats causing poor germination. Seeds will reach 4 to 7 percent moisture under the 20 percent humidity often seen in Colorado.

Here is a relative guide to the life expectancy of seeds stored under favorable conditions. Use it for deciding whether to keep or toss leftover seed.

Life expectancy in years
Bean 3
Beet 4

Broccoli 3
Brussels sprouts 4
Cabbage 4
Carrot 3
Cauliflower 4
Chinese cabbage 3
Collard 5
Corn 2
Corn salad (mache) 5
Cucumber 5
Eggplant 4
Endive 5
Kale 4
Kohlrabi 3
Leek 2
Lettuce 6

Muskmelon 5
Mustard 4
New Zealand spinach 3
Okra 2
Onion 1
Parsnip 1
Pea 3
Pepper 2
Pumpkin 4
Radish 5
Rutabaga 4
Salsify 1
Spinach 3
Squash 4
Swiss chard 4
Tomato 4
Turnip 4
Watermelon 4

Photo credit: Seed packets, Carl Wilson

October snow dump

Did you lose your garden? Mine is somewhere under the 18 inches of white stuff in the photo left. What good moisture for us! In dry Colorado, you never object to moisture however it comes (even if you secretly wish it to be doled out a little more gradually). This snow event will probably end up yielding about 1.5 inches of moisture when it melts this weekend. It’s predicted to be in the 50s F so the white will be a passing thing.

In addition to the moisture, snow is a good insulator. I’m not too worried about my annual ryegrass cover crop (photo right) that is coming up or my kale and other fall crops. They should be fine and the moisture will give them a boost.


Gardening resurgence in New Zealand - Like us, gardeners in the southern hemisphere are getting on board the trend towards more vegetable growing in the worldwide recession. See the news from the “kiwis.”

Photo credit: Snow in garden and Annual ryegrass - Carl Wilson

Evaluate tomato performance

Before memories fade, now is the time to evaluate what tomato varieties performed well for you this season.

The tomato variety that performed best in my southwest Denver garden was ‘Yellow Taxi’ (64 days, photo left) This was followed by the widely adapted All American Selection, ‘Celebrity’ (70 days). ‘Large Red’ (heirloom 82 days), ‘Sun Cherry’ (58 days) and ‘Green Zebra’ (heirloom 75 days) were poor performers. All were sorely tested by the July 20 hailstorm that hit the western Denver Metro area. ‘Yellow Taxi’ and ‘Celebrity’ recovered and produced.

The cool, early summer this year affected all Front Range tomato gardeners. Longer season varieties struggled more than others. Keep in mind that if you have part day shade, your days to harvest becomes longer because it takes 1 ½ of your part shade days or so to chalk up one day on the published days to harvest rating. For you, choosing short days to harvest varieties is a must.

What tomato varieties performed well for you in 2009? Make your notes to guide your choices in future years. Share your experiences with our readers and help everybody. Do note your location in your comment.

Photo credit: ‘Yellow Taxi’ tomato fruit, Carl Wilson